Nontoxic combination therapy with Amphotericin B (AmB) and 1,3-Bis (2-chloroethyl) -1-introsourea (BCNU) cures a transplantable syngeneic leukemia in AKR mice. Our previous studies strongly suggest, but do not prove, that AmB has an immunostimulant mechanism of effectiveness in this mouse leukemia model. the project outlined here is directed at attempts to quantitate the magnitude and diversity of immunostimulant properties of AmB. The project will also attempt to elucidate the cellular mechanism of AmB adjuvanticity by separate assays of the biological effects of AmB on thymus dependent (C) lymphocytes, thymus independent (B) lymphocytes, and macrophages. The experiments outlined here have a nuifying theme in attempts to quantitate the murine immune responses occurring in the presence and absence of AmB, to hapten protein conjugates, sheep erythrocytes, and transplantation alloantigens. These experiments should yield information of broad significance in immunobiology.